Flashcards in Chapter 7 - Bone Structure and Function Deck (53):
What are the 4 functions of the skeletal system?
1) provide support and protection
2) assist body in movements
3) participate in blood cell production
4) storage of mineral and energy reserves
what are the 3 main components of a long bone?
1) Diaphysis - shaft
2) Epiphyses - forms the distal and proximal ends of a long bone
3) Metaphyses - area btw diaphysis and epiphyses
How do bones store minerals and energy?
fats are stores in adipose tissue of yellow bone marrow.
calcium and phosphorus are also stored in the bone.
explain how bones assist in movements
muscles pull on bones to form movements
in what ways do bones provide structure and protection for the body.
-point of attachment for tendons and ligaments
-protects internal organs
what are the characteristics of Compact Bone
-strongest form of bone tissue
-resists stresses from weight and movement
-located on the outside of bone
What are the characteristics of spongy bone?
-located within compact bone
-supports and protects red bone marrow
What is Articular Cartilage and where is it found?
thin layer of hyaline cartilage that covers the epiphysis of long bones. It is on articular surfaces of bone.
What type of cartilage makes up the intervertebral discs and is found in the pelvis and knees?
A tough sheath of dense irregular CT located on the outside of the bone is called _______________.
A space that contains fatty yellow bone marrow in adults is called the _____________________.
What is the Endosteum?
a membrane that lines the medullary cavity
What are the general characteristics of Red Bone Marrow?
1) Hemopoietic (forms blood cells)
2) contains reticular CT (scaffolding), immature blood cells, and fat
how does Red Bone Marrow differ btw children and adults?
children: in spongy bone and medullary cavity of long bones. Children need more because they are still growing (higher metabolism)
Adults: located in portions of axial skeleton and proximal epiphyses of humorous and femur.
_______________ is a product of Red Bone Marrow degeneration.
Yellow Bone Marrow
what the general characteristics of Yellow Bone Marrow?
1) product of Red Bone Marrow degeneration.
2) stores fat
3) can convert back to red bone marrow during severe anemia
4) in adults it is found in medullary cavity of long bones
unspecialized bone stem cells.
mature into osteoblasts and then osteocytes
bone building cells
cells that break down bone
do not arise from osteoprogenitor cells
what is the chemical composition of bone?
30% collagen fibers
55% mineral salts: Calcium phosphate, calcium carbonate, trace elements (magnesium, fluoride, sulfate)
Units of compact bones are called _____.
Osteons are made up of _____________.
what are interstitial lamellae?
leftover fragments of older osteons that lie between osteons.
small spaces btw lamellae that house osteocytes are known as __________.
Osteocytes are located inside which structure?
small dendritic-like channels that connect lacunae
Blood, lymphatic tissue and nerves are located in this structure within a bone.
Spongy Bone contains osteons. True/ False.
what is trabecular?
lattice of thin columns of lamellae.
the process of forming new bone is called __________.
When does ossification occur?
1) initial formation (babies / children)
4) repair of fractures
breaking down and reforming new bone matrix is known as __________. what is important for this function?
balance between osteoblast and osteoclast activity
Describe bone growth.
-adolescents have an epiphyseal growth plate at the epiphyses of long bones
-contains hyaline cartilage
-where new bone is added
in adults, the epiphyseal growth plate become the _________________.
growing cartilage is replaced with calcified bone at what stage in life?
bone over growth is a result of ___________. this is called ____________.
more osteoblast activity than osteoclast activity.
osteoporosis refers to....
too much osteoclast activity relative to osteoblast activity
what factors are involved in bone metabolism
1) minerals - (calcium, phosphate, magnesium, manganese, fluoride)
2) viramins - (A, C, D, K, B12)
3)hormones - Human Growth Hormone, IGF, thyroid hormones, sex hormones
explain vitamin D synthesis
- UV light converts to precursor Vitamin D3 (cholecalciferol)
- In liver: Vitamin D3 is converted to Calcidiol (add OH-)
- In Kidney: Calcidiol is converted to calcitrol (Vitamin D) (by adding OH-)
- Vitamine D stimulates uptake of calcium from small intestine
How are calcium and phosphate levels balanced between blood and bone?
Parathyroid Hormone (Ca2+ is low) and calcitonin (from thyroid when Ca2+ is high)
What processes occur when blood calcium levels decrease?
1) parathyroid gland releases PTH
2) PTH and Calcitrol increase osteoclast activity
3) calcium is released into the blood
4) kidneys begin to excrete less calcium through urine
5) calitrol increases absorption of calcium from sm intestine into the blood
****Blood calcium levels increase
what processes occur when blood calcium levels are elevated
1) Thyroid gland releases calcitonin
2) calcitonin inhibits osteoclast activity
3) Kidneys are stimulated to increase the amount of calcium lost through urine
A Comminuted Fracture is ________________.
bone is splintered into several spall pieces between the main parts
When a bone is split into two or more pieces it is know as ____________.
what is a compound fracture?
broken ends of the bone protrude through the skin
a partial fracture in which one side of a bone breaks and the other is bent is known as ______.
a hairline fracture is _____.
fine crack in which sections of bone remains aligned (common in skull)
when one fragment of bone is firmly driven into another it is called....
A stress fracture is......
this fractures due to repeated, stressful impact such as running.
difficult to see on x-rays
may need a bone scan to accurately identify them
What are the 4 processes of bone repair?
1) Fracture Hematoma forms (6-8 hours after)
2) fibrocartilaginous callus forms (soft callus) - dense CT and collagen (3 weeks)
3)Boney callus forms - CT and collagen is replaced with bone (3-4 months)
4) Remodelling - compact bone is formed, osteoclasts clean up
What makes bone tissue stronger? Why?
-deposition of mineral salts
-increase osteoblast activity